*With butter or margarine, use half cup minus 2 tablespoons sour milk or buttermilk. With vegetable or any other shortening, use half cup sour milk or buttermilk. Have shortening at room temperature. Grease bottom of 13 x 23 cm pan. Preheat oven to 375 degrees. Measure into sifter, cake flour, baking powder, salt and sugar. Measure shortening into mixing bowl. Stir shortening just to soften. Stir in dry ingredients; add quarter cup milk and the mashed bananas and mix until all flour is dampened, then beat for 2 minutes on low speed. Add eggs, nut and remaining milk; beat for 1 minute. Pour into pan, bake for 30 to 35 minutes. (See Coconut Topping.) Coconut Topping: Cream butter or margarine and brown sugar together. Add milk and beat until smooth; add coconut. Let cake stand in pan for 5 minutes. Slice 3 or 4 bananas diagonally in 1 cm slices. Arrange bananas in four lengthwise rows on cake. Spread hot cake with coconut topping. Place under broiler for 3 minutes or until sugar is bubbly and coconut is brown. Serve warm.